In the technical field of chemical reactions, chemical reaction apparatuses are known in which various fluidized material mixtures are supplied to flow paths to cause chemical reactions, i.e., catalyst reactions with catalysts placed in the flow paths, thereby producing desired fluid materials.
These chemical reaction apparatuses have various scales and structures in accordance with their applications. For example, in a certain relatively small-sized chemical reaction apparatus, a micron-order or millimeter-order flow path is formed in a silicon substrate by using the micropatterning technology developed in the technology for fabricating semiconductors such as semiconductor integrated circuits, and fluid is supplied to this flow path to cause a chemical reaction.
FIG. 15 is an opened-up plan view showing an example of such a conventional chemical reaction apparatus. FIG. 16 is a sectional view taken along a line C-C in FIG. 15.
This chemical reaction apparatus includes a silicon substrate 1. On one surface of the silicon substrate 1, a fine zigzagged flow path 2 is formed by using the micropatterning technology developed in the semiconductor fabrication technology.
The two end portions of the flow path 2 are extended to substantially central portions of two predetermined end faces to form an inlet port 3 and outlet port 4. A catalyst layer 5 for performing a chemical reaction is formed on the inner wall surface of the flow path 2.
A glass substrate 6 is bonded to the above-mentioned surface of the silicon substrate 1. On the surface of the glass substrate 6 away from the surface opposite to the silicon substrate 1, a zigzagged thin-film heater 7 corresponding to the flow path 2 is provided.
The width of the thin-film heater 7 is made slightly smaller than that of the flow path 2. If the chemical reaction (catalyst reaction) in the chemical reaction apparatus induces an endothermic reaction under predetermined heat conditions, the thin-film heater 7 supplies predetermined thermal energy to the catalyst in the flow path 2 upon the chemical reaction.
A use example of this chemical reaction apparatus having the above arrangement will be explained below.
Recently, research and development for putting a power supply system using a fuel cell into practical use have been extensively done. A chemical reaction apparatus having the above arrangement can be used in this power supply system using a fuel cell. By this chemical reaction apparatus, as will be explained below, hydrogen can be produced from a power generation fuel gas and supplied to the fuel cell, and the power supply system using the fuel cell can be downsized.
While the thin-film heater 7 heats the interior of the flow path 2 to a predetermined temperature, the power generation fuel gas described above is supplied into the flow path 2 from the inlet port 3. This causes an endothermic reaction by the catalyst 5 in the flow path 2 to produce hydrogen and carbon dioxide as a byproduct. Of these products, only hydrogen can be produced by removing carbon dioxide from hydrogen. Electric power can be generated by supplying this hydrogen to the fuel cell.
In the above conventional chemical reaction apparatus, when the interior of the flow path 2 is heated by the thin-film heater 7, the two substrates 1 and 6 are also heated. Therefore, if the whole outer surfaces of these substrates 1 and 6 are exposed to the atmosphere, the thermal energy generated by the thin-film heater 7 is partially radiated to the outside from the surfaces of the substrates 1 and 6. This increases the thermal energy loss and worsens the energy utilization.